Advent is the period of four Sundays and weeks before Christmas .
Advent means 'Coming' in Latin. This is the coming of Jesus into the world. Christians use the four Sundays and weeks of Advent to prepare and remember the real meaning of Christmas.
There are three meanings of 'coming' that Christians describe in Advent. The first, and most thought of, happened about 2000 years ago when Jesus came into the world as a baby to live as a man and die for us.
The second can happen now as Jesus wants to come into our lives now.And the third will happen in the future when Jesus comes back to the world as King and Judge, not a baby.
Some people fast (don't eat anything) during advent to help them concentrate on preparing to celebrate Jesus's coming. In many Orthodox and Eastern Catholics Churches, Advent lasts for 40 days and starts on November 15th and is also called the Nativity Fast.
Christians often don't eat meat and dairy during Advent, and depending on the day, also olive oil, wine and fish. You can see what days mean now eating what foods on this calendar from the Greek Orthodox Archdiocese of America.
There are several ways that Advent is counted down but the most common is by a calendar or candle(s).